Field of the Invention
The present invention relates to a device for convective cooling of a functional assembly, wherein the device comprises:                a fan which in operation is designed to move air along a flow axis defined by the design and placement of the fan,        a flapper valve device including an air transit opening and a flapper valve assembly disposed therein including at least one flapper valve, which for changing the flow-through cross-section of the air transit opening is adjustable between a closed position, wherein the flow-through cross-section of the air transit opening along the flow axis is minimal, preferably zero, during operation, and an open position, wherein the flow-through cross-section of the air transit opening along the flow axis is maximal during operation, and        a control unit,wherein the fan and the flapper valve device are disposed at a distance from each other such that air moved due to operation of the fan flows through the air transit opening at least when the flapper valve device is in the open position.        
Devices of this kind for convective cooling are known, for example, from motor vehicles, where they are used inter alia to restrict the volume of air flowing through a radiator grill, such as into the engine compartment, by changing the available flow-through cross-section of the air transit opening. The air flow can be generated by the movement of the vehicle and branch off from the airstream thus generated. In the absence of this airstream or if the airstream is insufficient, the air stream can also be generated by the fan mentioned above.
By changing the flow-through cross-section of the air transit opening, motor vehicle cold-start phases can be shortened and thus the internal combustion engine can be warmed up to nominal temperature more quickly, which reduces the pollutant emissions from a motor vehicle.
Devices of this kind for convective cooling are used in particular for cooling of the cooling fluid, in particular the coolant, used for temperature control of the internal combustion engine. Likewise a device of this kind can be used to cool brake fluid or a lubricant, such as engine oil, thus in general to cool an operating fluid in the operation of a motor vehicle. For this reason the fan is preferably disposed such that an air stream generated thereby flows onto, around or through a heat exchanger circulating the operating fluid.
Likewise, the fan is disposed relative to the flapper valve device such that the air moved by the fan when in operation flows through the air transit opening when the opening is opened due to the adjusted operating position of the flapper valve device. The air moved by the fan can be air from the intake stream, that is, air flowing toward the fan to the vacuum side of the fan, or it can be air from the exhaust stream, i.e., air moving away to the pressure side of the fan.
Since the device described herein for convective cooling represents an emission-relevant system due to its influence on the pollutant emissions from a motor vehicle, with regard to the increasingly stricter legal requirements with respect to environmental matters, it is important that the cooling device be testable as to whether it functions properly or not. Such a testability ensures that any undesirable damages that increase the pollutant emission from an internal combustion engine can be quickly recognized and corrected.
Heretofore the flapper valve device has been monitored via a query of the position of a so-called “drive flap,” and even this monitoring takes place only indirectly via the actuator or actuators provided for adjusting the at least one flapper valve between its operating positions, and specifically using a so-called actuator calibration.
In many flapper valve devices in the prior art only one flapper valve of a plurality of flapper valves is driven directly by an actuator, only the so-called “drive flap.” The remaining flapper valves of the flapper valve device are coupled to the drive flap solely for coordinated movement and are thus moved only indirectly by the actuator.
However, monitoring of the operating position of the flapper valve device solely by monitoring of the position of the drive flap presumes that the flapper valve device is functional overall. Thus if the drive flap is detected in the correct position, but only the position of the drive flap is located in the detected position, whereas the remaining flapper valves assume a different position due to a defect in the movement coupling, then the result of the monitoring of the flapper valve device or of the device for convective cooling is incorrect overall.